CIPHER is a playable word

cipher Scrabble® Dictionary

verb
ciphered, ciphering, ciphers
to solve problems in arithmetic
46 Playable Words can be made from "CIPHER"
   2-Letter Words (7 found)
   3-Letter Words (20 found)
   4-Letter Words (13 found)
   5-Letter Words (4 found)
   6-Letter Words (2 found)